Hardening of steel



Patented Sept. 6, 1932 UNITED STATES PATENT OFFICE BUD'OLF RITPA, FRANKFORT-ON-TEE-MAIN, GERMANY, ASSIGNOR TO POMOSIN WERKE G. M. B. H., OF FRANKFOBT-ON-THE-MAIN, GERMANY, A COMPANY OF GER- MANY ' HARDENING OF STEEL No Drawing. Application filed April 23, 1931, Serial 1T0. 532,277, and in Germany April 30, 1930.

1 same as that of oils, which are particularly suitable for the hardening of steel.

Based on these facts, I have investigated the hardening of steel with pectin solutions and pectin extracts and have found'that these exhibit outstanding advantages for this purpose, it being understood that the procedure or manner of using these pectin solutions or extractsis the same as in the case of the oil customarily employed for hardening steel.

Thus it was found possible to obtain vary ing results, according to the concentration of the pectin solution so that depending upon the concentration of the pectin solution employed, various degrees of hardness, tenacity and brittleness of the hardened steel can be obtained.

The pectin solutions employed according to this invention ofier as compared with steel hardening oils, the advantage of accurate adjustability. Oil as is known, is immiscible with water, whereas mixtures of water and pectin can be prepared in any desired proportion.

A further advantage is that oil is combustible, while pectin solutions are not. Since to obtain high brittleness and hardness, soluthe like can be used with similar results. I

have found that pectinsolutions (or extracts,

which fact I attribute partly to the incombustible character of pectin, and partly to the fact that it excels as a poor conductor of heat.

What I claim is The process of treating steels and like metal alloys, which consists in plunging them while hot into a hardening pectin solution.

In testimony whereof I hereunto aifix my signature this 13th day of April, 1931.

.. RUDOLF RIPA.

the steel is generally introduced (plunged) into the hardening bath in. a glowing condition, this fact is of special importance.

The most important advantage is, however,

the low price of the pectin solutions, which are many times cheaper than hardening oils. Yet another advantage of the process of the invention is that the hardening and tempering, which have hitherto been eifected in two separate operations, can by a suitable regulation of the concentration of the pectin solution be carried out in one operation.

For the hardening of steels pectin solutions of 0.5 to 15% and over can be used. Instead of artificial'pectin solutions, natural pectin extracts, coming from portions of plants, whichcan be concentrated or diluted as desired, can be used. When it is desired as their equivalents) yield the best results, 

